A performance-controllable flow-state solidified mudstone filling slurry made of abandoned tunnel mudstone and a preparation method thereof

Abstract

This invention provides a fluidized solidified mudstone filling slurry with controllable performance, made from waste tunnel mudstone, and its preparation method, relating to the field of building materials technology. The fluidized solidified mudstone filling slurry of this invention comprises the following raw materials in parts by weight: 100 parts waste tunnel mudstone, 4-12 parts cement, 2-7 parts mineral powder, 0.24-1.12 parts admixture, and 55-75 parts water. This invention realizes the resource-based reuse of waste tunnel mudstone, not only further promoting waste utilization but also effectively reducing the amount of solid waste and mitigating environmental hazards. The fluidized solidified mudstone filling slurry prepared by this invention has significant advantages such as adjustable performance, low cost, and enhanced environmental friendliness. It can efficiently reinforce karst caves, resulting in a more stable cave structure that meets the requirements of pile foundation construction, ensuring safety during construction and subsequent applications.

Description

Technical Field

[0001] This invention provides a fluidized solidified mudstone filling slurry with controllable performance made from abandoned tunnel mudstone and its preparation method, belonging to the field of building materials technology. Background Technology

[0002] Karst regions, due to the long-term erosion of rocks by water, have formed various types of karst landforms and cave structures. Simultaneously, microcracks and joints developing within the rocks further damage the integrity of the rock mass, significantly reducing its strength and stability. This situation easily leads to uneven settlement, instability, and even collapse of karst foundations, seriously impacting engineering construction and safety, and even causing safety accidents. Therefore, effective reinforcement of karst caves is crucial, serving as a key measure to ensure project stability and a fundamental guarantee for construction safety.

[0003] In recent years, grouting technology, as a foundation treatment method, has developed into a relatively mature engineering technology. With its significant advantages such as strong construction feasibility, convenient operation, economic rationality, short construction period, and minimal impact on the surrounding environment, grouting technology has been widely used in infrastructure construction, mining excavation, transportation, and other fields. As the core of grouting engineering, grouting materials play a crucial role in filling and reinforcing pores in soil and rock, ground fissures, and underground karst caves. Its main functions include enhancing the mechanical strength of soil and rock, improving the bearing capacity of the foundation, and achieving seepage prevention and leakage plugging, thereby providing strong guarantees for the safety and stability of the project.

[0004] With rapid urbanization, numerous construction projects generate substantial amounts of construction waste, including slag and excavated soil. Construction slag is waste generated during site leveling or underground excavation, and is a type of construction waste. Each year, billions of cubic meters of construction slag, soil, and silt are excavated globally, most of which are considered waste soil and typically disposed of through direct dumping or landfill. While construction slag primarily originates from underground soil and rock, its pollution is relatively low, mainly manifesting as dust pollution, but this does not mean it is completely harmless. When the amount of construction slag is small, the risk is low; however, a significant increase in the amount can trigger serious geological disasters such as landslides. Furthermore, the transportation of this construction slag incurs high costs, further increasing the unnecessary economic burden. These issues highlight the importance and urgency of construction slag management and resource utilization.

[0005] Currently, commonly used cement-based grouting materials in karst grouting reinforcement projects include ordinary cement grout and cement-water glass two-component grout. However, these materials have many shortcomings in practical applications. Ordinary cement grout, due to its high water separation rate, strong fluidity, and excessively long gel time, is prone to grout loss in karst strata with well-developed fissures, making it difficult to effectively fill fissures or seal karst caves, thus failing to efficiently reinforce fractured rock layers and potentially polluting the groundwater environment. In contrast, while cement-water glass two-component grout has a shorter gel time, its low fluidity easily leads to grout pipe blockage, affecting pumping performance. Furthermore, cement grout aggregates generally exhibit high brittleness and are prone to cracking, resulting in insufficient mechanical strength and failing to meet the reinforcement requirements of complex karst strata. Therefore, there is an urgent need to develop and prepare grouting materials that exhibit excellent performance in terms of gel time, fluidity, stability, and mechanical strength to significantly improve the grouting reinforcement effect of karst strata with well-developed fissures and meet the safety and durability requirements of engineering construction. Summary of the Invention

[0006] Based on this, the present invention provides a fluidized solidified mudstone filling slurry with controllable performance made from abandoned tunnel mudstone and its preparation method. Specifically, the present invention is achieved using the following technical solution: A performance-controllable fluidized solidified mudstone filling slurry made from abandoned tunnel mudstone comprises the following raw materials in parts by weight: The abandoned tunnel contains 100 parts mudstone, 4-12 parts cement, 2-7 parts mineral powder, 0.24-1.12 parts admixture, and 55-75 parts water.

[0007] Preferably, the admixture is a thickener and an early-strength agent. The early-strength agent is a water-reducing agent with a water reduction rate of ≥8%, a water bleeding rate of ≤95%, and an air content of ≤4% (the early-strength agent used in the following embodiments of the present invention was purchased from Hongxiang Building Admixture Factory in Laiyang City, Shandong Province; the thickener is hydroxypropyl methylcellulose with a viscosity of 200,000, a methoxy group content of 22%, and a hydroxypropyl group content of 9%).

[0008] Preferably, the cement is 42.5 ordinary Portland cement with a specific surface area of ​​352 m². 2 / kg, initial setting time is 188min, final setting time is 239min.

[0009] Preferably, the mineral powder is S105 grade mineral powder with a density of 2.93 g / cm³. 3 It has a specific surface area of ​​628 m² / kg, a fluidity ratio of 102%, and a water content of 0.2%.

[0010] The water-to-solids ratio is the mass ratio of water to all solids. In the fluidized solidified mudstone filling slurry of this invention, the mass ratio of water to all solids, including abandoned tunnel mudstone, cement, mineral powder, and additives, is 0.5 to 0.66.

[0011] Preferably, the ratio of the total mass of cement and mineral powder in the fluidized solidified mudstone filling slurry to the mass of the abandoned tunnel mudstone is 0.08 to 0.16.

[0012] This invention also provides a method for preparing the performance-controllable fluidized solidified mudstone filling slurry made from abandoned tunnel mudstone, comprising the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

[0013] Compared with the prior art, the present invention has the following beneficial effects: This invention realizes the resource-based reuse of mudstone from abandoned tunnels, which not only further promotes waste utilization but also effectively reduces the amount of solid waste and mitigates environmental hazards. The fluidized solidified mudstone filling slurry prepared by this invention has significant advantages such as adjustable performance, low cost, and enhanced environmental friendliness. It can efficiently reinforce karst caves, resulting in a more stable cave structure that meets the requirements of pile foundation construction and ensures safety during construction and subsequent applications. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the preferred embodiments of this invention will be described in further detail below with reference to the examples. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0015] Example 1 A fluidized solidified mudstone filling slurry with controllable performance is composed of the following raw materials in parts by weight: 8.4 parts cement, 3.6 parts mineral powder, 0.84 parts admixture (including 0.24 parts thickener and 0.6 parts early strength agent), 100 parts abandoned tunnel mudstone, and 56 parts water.

[0016] The method for preparing the controllable performance fluidized solidified mudstone filling slurry includes the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

[0017] Example 2 A fluidized solidified mudstone filling slurry with controllable performance is composed of the following raw materials in parts by weight: 8.4 parts cement, 5.6 parts mineral powder, 0.84 parts admixture (including 0.28 parts thickener and 0.56 parts early strength agent), 100 parts abandoned tunnel mudstone, and 70.68 parts water.

[0018] The method for preparing the controllable performance fluidized solidified mudstone filling slurry includes the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

[0019] Example 3 A fluidized solidified mudstone filling slurry with controllable performance is composed of the following raw materials in parts by weight: 12 parts cement, 4 parts mineral powder, 0.96 parts admixture (including 0.32 parts thickener and 0.64 parts early strength agent), 100 parts abandoned tunnel mudstone, and 67.28 parts water.

[0020] The method for preparing the controllable performance fluidized solidified mudstone filling slurry includes the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

[0021] Example 4 A fluidized solidified mudstone filling slurry with controllable performance is composed of the following raw materials in parts by weight: 7.8 parts cement, 4.2 parts mineral powder, 0.6 parts admixture (including 0.24 parts thickener and 0.36 parts early strength agent), 100 parts abandoned tunnel mudstone, and 64.96 parts water.

[0022] The method for preparing the controllable performance fluidized solidified mudstone filling slurry includes the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

[0023] Example 5 A fluidized solidified mudstone filling slurry with controllable performance is composed of the following raw materials in parts by weight: 11.2 parts cement, 4.8 parts mineral powder, 0.64 parts admixture (including 0.32 parts thickener and 0.32 parts early strength agent), 100 parts abandoned tunnel mudstone, and 76.56 parts water.

[0024] The method for preparing the controllable performance fluidized solidified mudstone filling slurry includes the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

[0025] Example 6 A fluidized solidified mudstone filling slurry with controllable performance is composed of the following raw materials in parts by weight: 4.4 parts cement, 3.6 parts mineral powder, 0.32 parts admixture (including 0.16 parts thickener and 0.16 parts early strength agent), 100 parts abandoned tunnel mudstone, and 62.64 parts water.

[0026] The method for preparing the controllable performance fluidized solidified mudstone filling slurry includes the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

[0027] Example 7 A fluidized solidified mudstone filling slurry with controllable performance is composed of the following raw materials in parts by weight: 10.5 parts cement, 3.5 parts mineral powder, 0.42 parts admixture (including 0.28 parts thickener and 0.14 parts early strength agent), 100 parts abandoned tunnel mudstone, and 70.68 parts water.

[0028] The method for preparing the controllable performance fluidized solidified mudstone filling slurry includes the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

[0029] Example 8 A fluidized solidified mudstone filling slurry with controllable performance is composed of the following raw materials in parts by weight: 10.4 parts cement, 5.6 parts mineral powder, 0.48 parts admixture (including 0.32 parts thickener and 0.16 parts early strength agent), 100 parts abandoned tunnel mudstone, and 62.64 parts water.

[0030] The method for preparing the controllable performance fluidized solidified mudstone filling slurry includes the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

[0031] The karst pile foundation grouting reinforcement materials prepared in Examples 1-8 were tested, and the specific testing methods are as follows: Flowability: Tested in accordance with JHS A313 "Test Methods for Air-Entrained Mortar and Air-Entrained Grout" issued by the Japan Road Public Corporation.

[0032] Bleeding rate: Tested according to the "Test Method for Bleeding of Cement" (JC / T 2153-2012).

[0033] Setting time: Tested according to the method of GB / T1346-2011 "Standard consistency water requirement, setting time and soundness test method for cement".

[0034] 28-day unconfined compressive strength: tested according to the "Standard for Geotechnical Testing Methods" (GB_T50123-2019).

[0035] Water stability: The specimen size for water stability testing is the same as that for compressive strength testing, both being cylindrical specimens with a diameter of 50 mm and a height of 100 mm. Water stability testing involves pouring the prepared slurry into the mold, demolding it after 1 day, standard curing for 27 days, followed by immersion curing in water for 24 hours, and finally measuring the unconfined compressive strength of the specimen after immersion in water. The ratio of the unconfined compressive strength before and after immersion in water for 24 hours is the basis for judging water stability. The specific test steps are as follows: (1) Repeat the operation steps (1) to (3) of the specimen compressive strength test to prepare the slurry specimen.

[0036] (2) Standard curing: Immediately after demolding, wrap the specimen with plastic wrap to prevent moisture loss. Then, number the specimens again and finally transfer them to the standard curing box for curing under standard conditions for 27 days.

[0037] (3) After 27 days of curing, first remove the plastic wrap and check the integrity of the specimen. Divide the specimen into two equal parts according to the ratio. Test the five lateral compressive strength of the first part directly and record the values. Water curing is carried out on the second part. Next, prepare a water curing box and add water to a certain height in the box. Then, immerse the second part of the demolded specimen in a water tank at 20±2℃ for immersion curing. The water level should be more than 5cm above the top of the specimen. The immersion curing time is 24h.

[0038] (4) After the curing time is reached, take the specimen out of the water curing box and wipe the surface of the specimen with a towel to ensure that there is no large amount of water on the surface of the specimen; place the specimen on the electric lime soil unconfined pressure tester, ensure that the top and bottom surfaces are flat, and carry out the compressive strength test.

[0039] (5) Record the compressive strength of the specimens. Specimens with the same mix ratio should be tested multiple times. Each set of data uses 3 specimens. The final compressive strength is the arithmetic mean of the compressive strength of the 3 specimens.

[0040] (6) Calculate the ratio of the unconfined compressive strength of the second part after immersion in water to the unconfined compressive strength of the first part after direct standard curing for 27 days, and obtain the water stability of the specimen.

[0041] Shrinkage rate: Based on the "Standard for Geotechnical Testing Methods" (GB / T 50123-2019) and the characteristics of this fluidized solidified mudstone slurry, the method for testing shrinkage rate was improved. In this test, a ring sampler with a height of 20 mm and a diameter of 61.8 mm was placed on a glass slide lined with filter paper. The prepared slurry was poured into the ring sampler, and the surface of the ring sampler was smoothed with a scraper. The initial volume of the sample was measured, and after standard curing, the volume of the sample was measured after 3 days. The ratio of the difference between the initial volume of the slurry and the volume of the slurry after 3 days to the initial volume of the slurry is the shrinkage rate. The specific steps are as follows: (1) Check the integrity of the ring cutter and glass slide, wipe them with a clean towel, and ensure they are dry and clean.

[0042] (2) First, place the ring cutter in the center of the glass slide; then pour the freshly mixed slurry into the ring cutter; finally, use a scraper to smooth the slurry, ensuring that it is flush with the edge of the upper surface of the ring cutter.

[0043] (3) Calculate the initial volume of the test sample and record it as V; then place the ring cutter and the test sample into the standard curing chamber and perform standard curing under standard conditions for 3 days.

[0044] (4) After the curing time is reached, the volume of the sample after 3 days is measured and recorded as V1.

[0045] (5) Record the data and substitute it into formula (2) to calculate the shrinkage rate.

[0046] In the formula: β is the shrinkage rate; V is the initial volume of the slurry (mm³). 3 V1 is the volume of the slurry after 3 days (mm³). 3 ).

[0047] The test results are shown in the table below: The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A fluidized solidified mudstone filling slurry with controllable performance, made from mudstone from abandoned tunnels, characterized in that, The raw materials include the following parts by weight: The abandoned tunnel contains 100 parts mudstone, 4-12 parts cement, 2-7 parts mineral powder, 0.24-1.12 parts admixture, and 55-75 parts water.

2. The performance-controllable fluidized solidified mudstone filling slurry made from abandoned tunnel mudstone as described in claim 1, characterized in that, The additives are thickeners and early-strength agents.

3. The performance-controllable fluidized solidified mudstone filling slurry made from abandoned tunnel mudstone as described in claim 1, characterized in that, The cement is 42.5 ordinary Portland cement.

4. The performance-controllable fluidized solidified mudstone filling slurry made from abandoned tunnel mudstone as described in claim 1, characterized in that, The mineral powder is S105 grade mineral powder.

5. The performance-controllable fluidized solidified mudstone filling slurry made from abandoned tunnel mudstone as described in claim 1, characterized in that, The water-to-solid mass ratio of the fluidized solidified mudstone filling slurry is 0.5~0.

66.

6. The performance-controllable fluidized solidified mudstone filling slurry made from abandoned tunnel mudstone as described in claim 1, characterized in that, The ratio of the total mass of cement and mineral powder in the fluidized solidified mudstone filling slurry to the mass of mudstone from the abandoned tunnel is 0.08 to 0.

16.

7. The method for preparing a performance-controllable fluidized solidified mudstone filling slurry made from abandoned tunnel mudstone as described in any one of claims 1 to 6, characterized in that, Includes the following steps: The first step is to remove impurities from the mudstone in the abandoned tunnel and then dry it. The second step is to crush and sieve the dried mudstone from the abandoned tunnel to remove large soil particles. The third step is to weigh the sieved waste tunnel mudstone, cement, mineral powder, and additives according to the proportion, mix them evenly, and then add water and stir to obtain a uniform slurry, which can then be used to prepare the fluidized solidified mudstone filling slurry.

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